大体积混凝土结构应力场的粘弹塑性分析方法

根据混凝土材料强度、变形、损伤拉压显著不同的力学特性，分别在拉应变空间考虑粘弹性与损伤耦合、在压应变空间考虑粘弹塑性与损伤耦合，应用应变能等价原理建立了混凝土的粘弹塑性损伤本构模型。在粘弹塑性损伤本构模型中，混凝土的刚度退化和应变软化由正交各向异性损伤理论描述，弹塑性特性由内时理论来描述，内时理论没有屈服面，使模型的参数和方程大大减少，从而简化了非线性计算过程。考虑温度、徐变、自生体积变形、干缩变形等因素的影响，用增量一迭代法建立了大体积混凝土结构应力场的粘弹塑性有限元表达式。

A visco-elastic-plastic analysis method for stress field of massive concrete structures

On the basis of the different mechanical characteristics on strength,,deformation and damage between tension and compression of concrete, and in consideration of the coupling between visco-elasticity and damage in the tensile strain space and the coupling between visco -elastic -plasticity and damage in the compressive strain space,the visco -elastic -plastic constitutive model and damage evolution laws are established by applying the equivalent strain energy principle. The behaviors of stiffness degradation and strain softening of concrete are described by orthotropic damage theory. But its elastic-plasticity of concrete is described by endochronic theory. No yield surface is needed in endochronic theory so that the numbers of parameters and equations in the model are greatly reducedand the nonlinear calculation is simplified significantly. Considering the effect factors such as temperature, creep, self-grown volumetric deformation and shrinkage distortion etc.,the visco-elastic-plastic FEM expression for stress field of massive concrete structure is put forward by incremental iterative method.